Crystallization And Modification In High Magnetic Field Of Amorphous Alloys Used For Bipolar Plates

People now are paying focused attention to the proton exchange membrane fuel cell for its high efficiency and non-pollution. The bipolar plate is the most important part of the fuel cell blocking the development of the fuel cell for it is very expensive. Graphite and metal are the most popular materials used for bipolar plates .The conventional graphite bipolar plate in the proton exchange membrane fuel cell has a few disadvantages: bad mechanical property, difficulty in processing the tunnels, complicated technology about infiltrating dielectric. At present people become very interested in metal bipolar plate, though the problems that the existence of anode corrosion while it is working and the increase of cathode contact resistance for oxidation have not been resolved. The try to find a bipolar plate material with good properties and lower price is a very important and meaning thing.The amorphous alloys with special mechanical property, electric property and corrosion resistance property for its special structure can be easily produced in ribbons, which have a great plasticity in the supercooled liquid region. So the flow field can be compacted easily. We believe that this kind of amorphous alloy might be a material used for the bipolar plates in fuel cell in the future followed by modifyingThe structure, thermal stability, mechanical property ,electric conductivity and corrosion resistance of Ni60Nb(20-x)TaxTi15Zr5 amorphous alloys were studied . The result indicated that with more Ta, thermal stability, mechanical property, corrosion resistance of Ni60Nb (20-X) TaxTi15Zr5 amorphous alloys were improved ,however, electric conductivity changed a little. When Ta replaced Nb completely, alloy showed the best properties:large supercooled liquid region, high micro-hardness and corrosion resistance. The alloy consists of amorphous phase+Ni+Ni11Zr9+NiTa+Ni2.67Ti1.33+unknown phase isothermic annealed at 750℃.The optimum annealing condition is at 650℃ for 30min. We have got nanocrystalline alloys with an average grain of 18.43nm, crystallinity of 15.12% at 650℃ for 30min in a high magnetic field of 10T. The electroconductibility becomes improved accompanied by better corrosion resistance by annealing in high magnetic field. In the last we tried to analyze the reason why grain refinement and improved crystallization occur in high magnetic field.